1. Field of the Disclosure
The technology of the disclosure relates to fiber optic ribbon cables comprising multiple optical fibers disposed in a ribbon matrix to support multiple optical pathways.
2. Technical Background
Benefits of optical fibers include extremely wide bandwidth and low noise operation. In cases where high bandwidth is required between two interconnection locations, fiber optic cables may be used to provide sufficient bandwidth to communicate information between these locations.
In cases where greater optical interconnect density is required with multiple connection points in a small area, fiber optic ribbon cables may be used. Fiber optic ribbon cables provide multiple optical fibers disposed in parallel in a cable. As demand for higher bandwidth increases, interconnection technologies must accommodate more optical fibers or adapt other techniques to provide more bandwidth, for example, multicore optical fibers. At each of the interconnection locations, the end of each optical fiber must be precisely aligned with optical components to exchange optical information or unacceptable signal attenuation may occur. Optical fibers are typically optically coupled at the interconnection location using fiber optic connectors which enable efficient connection and disconnection of the optical fibers at interconnection locations.
Conventional connectors utilized with commercially-available single-core optical fibers use passive alignment or active alignment to ensure that the single-core optical fibers are properly located within the connector. Passive alignment allows an end of the single-core optical fiber to be inserted into a precisely-shaped circular opening of a ceramic ferrule to align the single core, which includes a single optical path, to a center of the circular opening. The passive alignment used for single-core optical fibers is not sufficient to align multicore optical fibers, because angular orientation is also required for alignment. Specifically, when a multicore optical fiber is inserted into an opening of a ferrule, not every core (including an optical path) of the multicore optical fiber will be located at a center of the opening of the ferrule. Precise angular orientation of each of the multicore optical fibers within the ferrule is required for alignment to a fiber optic connector. Conventional fiber optic connectors for single-mode optical fibers using passive alignment techniques do not align optical fibers in accordance with angular orientation and thereby are unsuitable for multicore optical fibers.
Alternatively, active alignment is the customized placement of an end of an optical fiber at an interconnect point in terms of X, Y, and Z coordinates and also angular alignment, depending on optical fiber type, to meet the optical transmission requirements of the optical fiber at that interconnection point. Active alignment typically requires time-consuming optical diagnostic equipment to ensure that each optical fiber is properly orientated within the connector before being fixed into place. In this regard, multicore optical fibers are even more difficult and time consuming to actively align compared to single-mode optical fibers given the additional requirement of angular alignment.
Regardless of whether passive or active alignment techniques are used, connecting multiple multicore optical fibers combined in a ribbon cable provides additional problems because the inefficiencies of each of the alignment techniques are accumulated. A ribbon cable includes multiple optical fibers orientated in parallel and connected by a ribbon matrix (or outer cable jacket) holding the optical fibers together. Each optical fiber must be aligned to the connector. Specifically, to actively align a multicore optical fiber in a ribbon cable, a ribbon matrix (the outer cable jacket) may have to be substantially removed or “cut back” in order to free optical fibers needing large angular adjustments to complete alignment at an interconnection point. Cutting back the ribbon matrix may be infeasible because substantial cutting of fiber optic ribbon cables is overly time consuming. Moreover substantially removing the ribbon matrix (“cutting back”) exposes portions of the optical fibers to damage. In this regard, improved approaches are needed to provide a high density of easily connectorized optical paths in a cost effective manner.